The present invention relates generally to the area of intraocular lens and use thereof to correct visual problems. More particularly, this invention provides a lens and method of use thereof for the correction of a lack of accommodation. The lens can be inserted into a human eye through a 1.5 millimeter or smaller incision.
Doctors trained in ophthalmology routinely surgically extract cataract-impaired natural crystalline lenses from patients""eyes and subsequently implant artificial lenses to prevent blindness.
Using an intraocular lens for correction of visual problems is currently problematic. In order to insert an intraocular lens, an incision is made through the cornea or sclera. The new lens is passed through the incision into the anterior chamber of the eye. The inserted lens is then positioned over the pupil and anchored either anteriorly to or posteriorly from the iris, or other structure of the eye. Unfortunately, the making of the incision causes astigmatism of the cornea.
Alternative lens materials are also currently used for the replacements of the natural lenses of cataract patients. One such alternative lens material is an acrylic that has a lower molecular weight than PMMA. This lower-weight acrylic lens is softer than PMMA so it can be folded in a U-shape. However, if not handled very carefully, the lower-weight acrylic will crease, rendering it unusable. In addition, the material is soft enough to adhere to itself if it is rolled or folded far enough to allow overlapping.
Another alternative lens material is silicone, the same material that is used in breast implants. The silicone collects protein in some patients, giving a yellow appearance and reducing the passage of light. The protein can become so dense as to create the appearance of a secondary cataract, significantly reducing the patient""s ability to see. This is usually a lesser concern for cataract patient, when compared to the blindness, which would result from the cataract. Also, most cataract patients tend to be elderly so the protein build-up might not advance too far during their lifetimes. For some cataract patients, though, the protein build-up necessitates that the silicone lens be removed and replaced. Because of the problems associated with protein build-up, silicone cannot be used to make long-term intraocular lenses for implantation into younger persons.
Two inventions for a deformable intraocular lens are set forth in U.S. Pat. No. 4,573,998 issued March 1986, to Mazzocco; and U.S. Pat. No. 5,522,890 issued June 1996, to Nakajima et al. These inventions employ a lens made of a molded elastic material. They do not suggest the use of PMMA, nor do they suggest rolling an extremely thin lens to allow an incision size considerably smaller than required for the folded lens.
Other inventions generally related to the art of optical lenses include: U.S. Pat. No. 4,254,509 issued March 1981, to Tennant (Accommodating Intraocular Implant); U.S. Pat. No. 4,585,456 issued April 1986, to Blackmore (Corrective Lens for the Natural Lens of the Eye); U.S. Pat. No. 4,655,775 issued April 1987, to Clasby (Intraocular Lens with Ridges); U.S. Pat. No. 4,769,035 issued September 1988, to Kelman (Artificial Lens and the Method for Implanting Such Lens); U.S. Pat. No. 4,795,462 issued January 1989, to Grendahl (Cylindrically Segmented Zone of Focus Artificial Lens); U.S. Pat. No. 4,816,032 issued March 1989, to Hetland (Arrangement in an Intraocular Anterior Chamber Lens); U.S. Pat. No. 4,950,290 issued August 1990, to Kamerling (Posterior Chamber Intraocular Lens); U.S. Pat. No. 4,994,080 issued February 1991, to Shepard (Optical Lens Having at Least One Stenopaeic Opening Located in the Central Area Thereof); U.S. Pat. No. 5,076,684 issued December 1991, to Simpson et al. (Multi-Focal Diffractive Ophthalmic Lenses); U.S. Pat. No. 5,098,444 issued March 1992, to Feaster (Epiphakic Intraocular Lens and Process of Implantation); U.S. Pat. No. 5,166,711 issued November 1992, to Portney (Multifocal Ophthalmic Lens); U.S. Pat. No. 5,229,797 issued July 1993, to Futhey et al. (Multifocal Diffractive Ophthalmic Lenses); U.S. Pat. No. 5,258,025 issued November 1993, to Fedorov et al. (Corrective Intraocular Lens); U.S. Pat. No. 5,480,428 issued January 1996, to Fedorov et al. (Corrective Intraocular Lens). None of these inventions solves the above-disclosed problems associated with currently known deformable intraocular lenses.
A deformable artificial intraocular lens for implantation into the human eye is disclosed herein. The lens is used for the correction of myopia, hyperopia, presbyopia, astigmatism, or for implantation after cataract surgery. The lens optic consists of one smooth optical surface. The second optical surface is a series of annular concentric rings. The rings allow the lens to have extremely thin edges, which reduce glare, halos, and distortion. The rings also allow the overall thickness of the lens to be significantly thinner than a standard lens. This allows the lens to be inserted through an incision of 1.5 millimeters or smaller. A standard lens currently passes through an incision that is approximately 3 millimeters. The rings on the second surface are adjusted to reduce the spherical aberrations from the design of the first surface optic being spherical. Such a thin lens also reduces coma, and other Third Order Theory Aberrations (Fundamentals of Optics, Francis A. Jenkins and Harvey E. White, Fourth Edition, Copyright by McGraw-Hill, Inc. 1950 renewed in 1957 and 1976, page 151 through 160), which also create halos and glare.
Also disclosed herein is a method of correcting a loss of accommodation comprising removing a natural crystalline lens from the eye and inserting an intraocular lens in the eye. In certain embodiments, the method further comprises unrolling the intraocular lens so that a haptic footplate contacts the natural lens sac or the ciliary body in order to hold the intraocular lens in position and produce a minimum radial force on the eye.
Accordingly, one aspect of the present invention is an intraocular lens, comprising an optical portion having a first optical surface, wherein the optical portion is constructed of a material which is biologically compatible with a tissue of an eye, the optical portion having a predetermined maximum thickness under which the material may be rolled without exceeding the elastic limit of the material, said optical portion having a predetermined minimum thickness above which the material retains said normal shape, wherein the intraocular lens is deformed for passage through an incision having a length smaller than about 1.5 millimeters so that the intraocular lens is placed into the eye; the optical portion having a second optical surface, wherein the second optical surface comprises a central disk which is radially surrounded by a series of annular rings, the central disk and the series of annular rings forming a series of radial steps along the second optical surface so that a focal length from an annular ring is adjusted to focus at a same point as a prime meridian of the lens, wherein the second optical surface and the first optical surface have a minimum separation of 0.025 mm and a maximum separation of 0.45 mm; and an anchoring portion attached to the optical portion, wherein the anchoring portion is constructed of a material which is biologically compatible with a tissue of an eye, wherein the anchoring portion is capable of biasing against a support structure of the eye. In certain embodiments, the second optical surface and the first optical surface have a minimum separation of 0.025 mm and a maximum separation of 0.065 mm.
Another aspect of the present invention is that the first optical surface and the second optical surface are of a predetermined convexity for obtaining a particular focusing power. In certain embodiments, the first optical surface and the second optical surface are of a predetermined concavity for obtaining a particular focusing power. In still other embodiments, the first optical surface is of a predetermined convexity for obtaining a particular focusing power, and the second optical surface is of a predetermined concavity for obtaining a particular focusing power. In other embodiments, the first optical surface is of a predetermined concavity for obtaining a particular focusing power, and wherein the second optical surface is of a predetermined convexity for obtaining a particular focusing power. In yet another embodiment of the present invention, the first surface is of a predetermined concavity for obtaining a particular focusing power, and wherein the second optical surface is of a predetermined concavity for obtaining a particular focusing power.
Another aspect of the present invention is the ultra thinness of the anchoring portion. In certain embodiments, the anchoring portion has a thickness of about 10 microns to about 100 microns. In other embodiments, the anchoring portion has a maximum thickness of about 100 microns. In other embodiments, the anchoring portion comprises a plurality of anchoring footplates or a plate haptic.
Still another aspect of the present invention is a lens constructed of an acrylic material, a hydrophilic acrylic material, a hydrophobic acrylic material, any semi-rigid material having a thickness that is less than the elastic limit of the semi-rigid material, hydrogel, polymethylmethacrylate, or a material having an index of refraction from about 1.4 to about 2.0.
Another aspect of the claimed invention is the method of using the intraocular lens. In certain embodiments, a method of correcting a visual defect is provided. The method includes providing an intraocular lens as described herein, warming the intraocular lens to a temperature from about 90 degrees F. to about 150 degrees F., making an incision having a length of less than 1.5 mm in an eye, removing a natural lens of the eye, deforming the intraocular lens, cooling the intraocular lens to a temperature from about 60 degrees F. to about 80 degrees F., inserting the intraocular lens into the eye through the incision, contacting the intraocular lens with an intraocular fluid within the eye so that the intraocular lens warms and unrolls, and positioning the intraocular lens so that the anchoring portion biases against the support structure of the eye. In certain embodiments, positioning the intraocular lens further comprises biasing the anchoring portion against an anterior and posterior capsule structure, wherein biasing produces a minimum radial force on the eye. In still other embodiments, positioning the intraocular lens further comprises biasing the anchoring portion against zonules and a posterior iris, wherein biasing produces a minimum radial force on the eye, so that the anchoring portion of the intraocular lens is held in a fixed position.
Another aspect of the present invention is deforming the intraocular lens. In certain embodiments, the lens is rolled around a rod. In other embodiments, the lens is rolled around itself. In certain embodiments, the incision is repaired.
Once rolled and passed through the cornea, the implanted intraocular lens may be placed in a position. In certain embodiments, the implanted lens may be positioned anterior to the iris, in the anterior chamber of the eye. If this position is chosen, the haptic edge of each of the haptic fingers will be biased against the anterior chamber angle 31, the angle formed by the cornea and root of the iris and behind the trabeculum. Once positioned and allowed to unroll, the implanted lens will return to its original shape.
Alternatively, the implanted lens may be positioned posteriorly from the iris, and rest in front of the capsule of the natural lens of the eye. If this position is chosen, the haptic edge of each of the haptic fingers will be biased against the zonules and posterior iris surface or ciliary sulcus. The implanted lens is able to be placed posteriorly from the iris because of the thinness of the implanted lens.
The lens may also be implanted into the capsule that contained the natural lens after removal of the natural lens. One reason for the removal of the natural lens is a clouding of the natural lens, cataract. A second reason for removing the natural lens is to allow placement of an intraocular lens for cases of poor visions caused by extreme cases of myopia or hyperopia.
Another aspect of the present invention is using the lens disclosed herein to correct visualization of glare, halos, to reduce coma, and to correct spherical aberrations. In certain embodiments, the lens moves in order to correct a lack of accommodation. In certain embodiments, the intraocular lens moves toward an anterior surface of the eye when a ciliary muscle in the eye relaxes
While positioning the intraocular lens, in certain embodiments, the anchoring portion is curled toward the anterior surface of the capsule structure. In other embodiments, the anchoring portion is curled toward the posterior surface of the capsule structure.
Another aspect of the invention is a lens having a marker to indicate the direction of the lens.
The present invention is a deformable intraocular lens that may be rolled or folded for insertion into the human eye to correct common vision problems or for the replacement of the natural lens after cataract surgery. The lens is deformable because all portions of the lens are manufactured to a thickness, which is within a predetermined range of thicknesses. More particularly, at the first end of the range, the thickness of the lens is less than a maximum material thickness, the threshold under which the material is flexible. At the second end of the range, the thickness of the lens is also greater than a minimum material thickness, the threshold above which the lens material will retain its pre-flexed shape subsequent to flexing. The novel design also enables the deformable lens to possess any desired convexity or concavity, which would be required for correction of visual problems. Of course, the deformable lens of the present invention may also be constructed from any other biologically compatible material that can be manufactured thinner than a pre-determined maximum material thickness to be rolled or folded for passage through a small incision in the cornea or sclera.
An anchoring portion is attached to the optical portion to securely position the deformable intraocular contact lens, anteriorly to the natural lens of the eye. In certain embodiments, the lens also has a non-optical transition area interconnecting the anchoring means to the optical portion of the lens. The transition area has a thickness of approximately 0.025 mm. The anchoring means comprises a pair of haptic fingers extending from the transition area and circumvolving the optical lens. The thickness of the haptic fingers is preselected to provide the optimal combination of strength and flexibility. The outer circumference of the haptic finger comprises the haptic edge. The haptic edge of the implanted lens is biased against the intraocular tissues. The thickness of the haptic edge is preselected to provide minimal stress to the eye tissues.